/**
 * @title 实现拖动
 * @description 实现节点的拖动逻辑。
 */

import * as React from 'react'
import styled from 'styled-components'

import { Tree } from '@alicloudfe/components'

const TreeNode = Tree.Node

const x = 3
const y = 2
const z = 1
const gData = []

const generateData = (_level, _preKey, _tns) => {
  const preKey = _preKey || '0'
  const tns = _tns || gData

  const children = []
  for (let i = 0; i < x; i++) {
    const key = `${preKey}-${i}`
    tns.push({ label: key, key })
    if (i < y) {
      children.push(key)
    }
  }

  if (_level < 0) {
    return tns
  }

  const level = _level - 1
  children.forEach((key, index) => {
    tns[index].children = []
    return generateData(level, key, tns[index].children)
  })
}

generateData(z)

class Demo extends React.Component {
  constructor(props) {
    super(props)

    this.state = {
      gData
    }
  }

  onDrop(info) {
    if (!info.dragNode) {
      return
    }
    const dragKey = info.dragNode.props.eventKey
    const dropKey = info.node.props.eventKey
    const dropPosition = info.dropPosition

    const loop = (data, key, callback) => {
      data.forEach((item, index, arr) => {
        if (item.key === key) {
          return callback(item, index, arr)
        }
        if (item.children) {
          return loop(item.children, key, callback)
        }
      })
    }

    const data = [...this.state.gData]
    let dragObj

    loop(data, dragKey, (item, index, arr) => {
      arr.splice(index, 1)
      dragObj = item
    })

    if (info.dropPosition === 0) {
      loop(data, dropKey, (item) => {
        item.children = item.children || []
        item.children.push(dragObj)
      })
    } else {
      let ar
      let i
      loop(data, dropKey, (item, index, arr) => {
        ar = arr
        i = index
      })
      if (dropPosition === -1) {
        ar.splice(i, 0, dragObj)
      } else {
        ar.splice(i + 1, 0, dragObj)
      }
    }

    this.setState({
      gData: data
    })
  }
  render() {
    const loop = (data) =>
      data.map((item) => {
        if (item.children) {
          return (
            <TreeNode key={item.key} label={item.key}>
              {loop(item.children)}
            </TreeNode>
          )
        }
        return <TreeNode key={item.key} label={item.key} />
      })

    return (
      <Tree
        draggable
        selectable={false}
        isLabelBlock
        defaultExpandedKeys={['0-0', '0-0-0', '0-0-0-0']}
        onDrop={this.onDrop.bind(this)}
      >
        {loop(this.state.gData)}
      </Tree>
    )
  }
}

export default function DemoComponent() {
  const content = <Demo />
  return <Style>{content}</Style>
}
const Style = styled.div``
